Good submission.
Spike did not kill, and I suspect they were meant to.
The crumbling platforms did not always crumble, and I think they should do after second or two even if it were single jump of.
The game needs a background image, the blue color is just so bland, even if it is as simple as a gradient between colours would be good.
I landed in a hole that I could not jump out of or kill myself to reset.